Industrial Field of Utilization
The present invention relates to a process for producing an imidazole derivative. More particularly, it relates to a process for producing an imidazole derivative represented by the chemical formula [I]: ##STR3## which is useful for hypertension, congestive heart failure, renal failure, glaucoma, hyperuricemia and the like, in which complicated steps are avoided.
The above compound is an angiotensin II antagonist and is thus useful as an agent for preventing or treating hypertension, congestive heart failure, renal failure, glaucoma, hyperuricemia and the like. The present inventors have found that drugs of this class have longer shelf life, higher activity, rapid manifestation of action upon intravenous injection, good absorbability into the body upon oral administration, lower toxicity and long-lasting action. These novel compounds are imidazole derivatives having the hydrazine cross-linking structure represented by the formula: ##STR4## as described in Japanese Patent Application No. 3-277537, No. 3-323474, No. 4-095191 and No. 4-216809 and published PCT application WO 93/08193, published Apr. 29, 1993, which claims the benefit thereof. In the above applications, we reported the imidazole derivative [I] represented by the chemical formula: ##STR5## had particularly good effects. And we disclosed, in the above patent applications and Japanese Patent Application No. 5-060067, that this imidazole derivative can be synthesized according to the following route (Reaction scheme 1). In the route, a compound (1) is first protected with benzyl group, and after a few steps, the protected compound is debenzylated by hydrogenolysis to give a compound (4) and thereafter, a biphenyltetrazole part is linked thereto to give an end compound [I]. However, the above route has the problems in production efficacy and economical properties. In this regard, Richard F. Shuman et al. reported an improved process for producing biphenyltetrazoles which are an intermediate useful for production of angiotensin II antagonist in U.S. Pat. No. 5,039,814. ##STR6##